The use of single-serving or single-dose packages, such as capsules, cartridges or pods, for the preparation of hot beverages such as coffee and the like is becoming more and more popular. Use of capsules and other single-serving packages is extremely practical, since the ingredients for the preparation of the beverage remains contained in the capsule and can be easily removed by discharging the spent capsule from the machine, without the machine becoming soiled by residual products derived from the beverage infusion or preparation process.
Usually, a beverage preparing system is characterized by a beverage brewing unit configured for receiving one single kind of capsules only. The capsules are designed and manufactured based on the kind of beverages they are intended for. Disposable capsules are for example used for the preparation of filter coffee, wherein hot water at relatively low pressure is percolated through the capsule to extract the flavors from coffee powder sealingly contained in the capsule. Piercers are provided to pierce the top and the bottom walls of the capsule and allow hot brewing water to flow through the capsule. Devices and systems using filter capsules or cartridges of this kind are disclosed for example in U.S. Pat. No. 6,655,260.
Disposable capsules or cartridges are also used for the preparation of espresso coffee. This kind of beverage is brewed by flowing hot pressurized water through the coffee-powder containing capsules. The relatively high brewing pressure ranging usually between 10 and 15 bars, generates a layer of cream on top of the beverage, which characterizes the typical espresso coffee. Espresso-coffee cartridges or capsules are usually smaller than filter coffee capsules and require a differently shaped brewing chamber.